Magnetic properties of ball-milled alloys Gd100-xNix (x=25, 40, 50)

Magnetic and magnetothermal properties of ball-milled Gd100-xNix (x = 25, 40, 50) alloys were studied. The second-order magnetic transition is observed in all samples at the Curie temperature, which decreases significantly with increasing Ni content. The Curie temperatures are 123 K for Gd75Ni25, 99 K for Gd60Ni40 and 73 K for Gd50Ni50. With a change in the applied magnetic field to 5 T, the maximum values of the isothermal magnetic entropy change were found to be 8.0 J/(kg K), 7.7 J/(kg K) and 9.6 J/(kg K) for ball-milled Gd75Ni25, Gd60Ni40 and Gd50Ni50 alloys, respectively. The refrigerant capacity diminishes with increasing of the Ni concentration from 570 J/kg for Gd75Ni25 up to 490 J/kg for Gd50Ni50. The critical exponents 8 determining the field dependence of the magnetization near the Curie temperature were obtained from data on the refrigerant capacity and magnetization isotherms.